[U-Boot] [PATCH 6/9] ARM: Implement CONFIG_SKIP_LOWLEVEL_INIT for arm926ej-s

Albert ARIBAUD
2011-04-25T07:30:50Z

Hi Wolfgang et al.,

(replying both to 5/9 and 6/9 here)

Le 25/04/2011 01:55, Wolfgang Denk a ?crit :

> This is an inconsistency between architectures which I dislike.

Then these two config options could be defined for other architectures
as well.

> Also, what in case we should want to skip only cpu_init_crit and not
> lowlevel_init? If we need to handle these separately, then we need 2
> CONFIG options.

Agreed this complete separation could be useful in case U-Boot is not
the code executed on startup, and this startup code does the CPU
initialization but leaves the rest to U-Boot for commodity.

> How can the SDRAM be initialized when the CPU is not?

Debugging sessions come to mind, where the debugger resets the target
and initializes SDRAM to load the target code. I've also seen cases on
multiple-core ICs where an ARM core starts with SDRAM access already
working, but U-Boot was not involved.

The idea is that during board bring-up, rather than have people try and
neutralize some code in assembly language startup files, they just
temporarily define the configuration options CONFIG_SKIP_* in their
board's config header file (and, for those boards that have an IPL of
some sort before U-Boot, they keep the relevant CONFIG_SKIP_* there once
debugged).

> Best regards,
>
> Wolfgang Denk

Amicalement,
--
Albert.